OXFORD, Ohio -- Miami University seniors cited in back-to-back disturbances near campus may participate in graduation ceremonies today but still face possible university sanctions, MU officials said Saturday.

Twenty-two more people were charged early Saturday with misdemeanors after police clashed for a second night in a row with unruly crowds on High Street.

Only eight of those were MU students, said Oxford Police Lt. Dan Umbstead.

He said he did not know how many MU students were involved in a similar confrontation early Friday. Media reports of the first disturbance may have attracted a rowdier crowd the next day, he said.

Miami seniors cited by police risk their diplomas, suspension or dismissal from school, said university officials, who planned Saturday to hand-deliver letters on possible disciplinary action to the seniors involved.

Eight seniors scheduled to graduate today were among 23 people arrested in the first incident early Friday when a large end-of-school celebration turned to vandalism and hurling bottles at police. Miami spokesman Richard Little said it will take weeks for students accused in the ruckus to have their cases reviewed in university disciplinary hearings.

"They put themselves in jeopardy of not receiving a degree, or certainly delaying the receiving of their degrees," he said. Police said the 22 citations issued Saturday after the second disturbance were for either disorderly conduct or failure to disperse.

The 200 young adults gathered on High Street early Saturday did not repeat the vandalism of the night before, when a book store sustained $5,000 in property damage, Oxford Police Sgt. Barry Gray said. But some showed more hostility toward police, who were trying to clear crowds blocking the sidewalks after uptown bars' 2 a.m. closing.

Compared to the previous night's rowdy gathering of more than 500, "there wasn't as great a number of people Friday night," said Sgt. Gray, shift commander for Oxford Police both nights. "However, their activities -- rather than destruction of property -- turned a little more violent toward us."

When police tried to move people out of the area around 2:15 a.m., he said, officers were struck with bottles and retreated.

"We were willing and ready to let them go home on their own until we were pelted with objects from the crowd," Sgt. Gray said.

Along with Miami University and Oxford Township police, officers from four other Butler County agencies -- some in riot gear and using pepper spray -- responded when the disturbance escalated.

One officer who was struck sought medical treatment for a minor hand injury, police said. They reported no other injuries.

Saturday morning's repeat surprised the manager of DuBois Book Store, where a trailer containing computer equipment had been overturned the previous night and canvas tents were ripped up. Damage to the trailer and tents cost the store $5,000, manager John DuBois said.

"Last night, I would have guessed with all the increased police activity, that it was going to be quiet," he said Saturday.

While Mr. DuBois welcomed the extra security, another uptown merchant said the attention from police and news media exacerbated the tensions.

"It all has to do with cabin fever, the stress of finals, too much police presence and too much press," said Ned Stephenson, owner of the Bagel & Deli Shop, a popular late-night hangout for students.

Next door, Miami senior Paul Barnes, 21, watched Saturday morning's crowd and police clash from the Phi Gamma Delta fraternity house. After Friday morning, "students had seen a lot of the hype on the news. I think they were responding to that more than anything else," Mr. Barnes said. "Frankly, I think the police responded a little too forcefully."

But Sgt. Gray said police could not take any chances after watching the partying get out of control.

"I have not seen this extent of cabin fever," said Sgt. Gray, a 16-year veteran in Oxford. "Never before have we had a situation in 16 years that I'm aware of where the crowd has overturned trailers and torn up canopy tents."